[M-IS05] 南大洋・南極氷床が駆動する全球気候変動

[MIS05-P12] Reconstruction of ice sheet dynamics in Totten Glacier/Aurora Subglacial Basin, East Antarctica during the Last Interglacial

*関 宰¹、飯塚 睦¹、堀川 恵司¹、van De Flierdt Tina²、池原 実³、入野 智久⁴、板木 拓也⁵、杉崎 彩子⁵ (1.北海道大学低温科学研究所、2.インペリアルカレッジロンドン、3.高知大学、4.北海道大学地球環境科学研究科、5.産業技術総合研究所)

キーワード：南極氷床、オーロラ海盆、トッテン氷河、最終間氷期

The Totten Glacier is one of the largest glaciers in East Antarctica. Recent observations suggest that the Totten Glacier is vulnerable to ocean warming. Ice mass loss in the Aurora Subglacial Basin, which locates behind and connects to Totten Glacier, could potentially cause a 3.5 m rise in global sea level. However, the sensitivity of the glacier-ice sheet system to ongoing global warming remains uncertain. A better understanding of Antarctic ice sheet dynamics in the warm past provides useful insights into projecting ice mass loss in the future. The Last Interglacial (LIG: 115-130 ka), which is characterized by temperatures 1 ºC warmer than the current interglacial climate, is often considered as a possible analogue for the future warm climate. Previous studies suggest significant ice mass loss in West Antarctica and the Wilkes Subglacial Basin during the LIG. However, ice sheet dynamics in the Aurora Subglacial Basin during the LIG remain an enigma. In this study, we attempt to reconstruct ice sheet dynamics in the Aurora Subglacial Basin during the LIG based on analysis of geochemical provenance proxies in two marine sediment cores, PC404 and PC504, collected off East Antarctica. Our data, together with Antarctic ice core isotope records in EDC and Vostok, suggest that the ice extent in the Aurora Subglacial Basin fluctuated dynamically during the LIG.